Washing machine with hollow agitators

ABSTRACT

A washing machine includes a horizontally rotatable drum having a drum shell. Hollow agitators are disposed on the inside of the drum and have a base as part of the drum shell and at least one inlet opening to allow lye into the hollow space. Outlet openings are located on a top region of each agitator for allowing lye to pour out upon rotation to an elevated position. A fixed barrier located in the hollow space of each agitator serves to divide the space to define a chamber such that upon rotation from a lowest position, the chamber fills with lye, and upon further rotation the lye flows out of the outlet openings.

The invention relates to a washing machine with a washing drum that is driven in a horizontally rotatable manner in an outer tub and with hollow agitators disposed on the inside of a drum shell, each having an agitator base as part of the drum shell, in which agitator base at least one inlet opening is incorporated, with constituent amounts of a lye located in the lower apex of the outer tub flowing into the hollow space of the agitator through the corresponding inlet opening and, after a further rotation of the washing drum into an elevated position of the agitator, pouring out of the hollow space by way of outlet openings in the top region of the agitator removed from the agitator base into the interior of the washing drum, as well as a method for operating said washing machine.

Such a washing machine is known from DE 38 03 195 A1, wherein washing liquor flows into the hollow space through scoop holes incorporated in the sides of the agitator ribs, pouring from there out of outlet openings over the washing from a higher position as the washing drum rotates. To wet the washing in both directions of rotation, the scoop holes can be sealed by means of moving seals located inside. The seals of the scoop holes at the front in the direction of rotation are opened by the back pressure of the lye or free washing liquor generated during drum rotation and the rear scoop holes are closed correspondingly. Such an arrangement is comparatively complex from a structural point of view and susceptible to wear on account of the moving parts.

A further agitator rib configured as a scooping device is known for example from DD-PS 37 560. Here paddles are disposed within the agitator hollows. As they pass through the sump at the bottom of the outer drum, the parts of the paddles projecting above the drum shell scoop up washing liquor, which they convey into the inner space of the drum during the upward movement by way of the holes disposed in the side of the agitator. Such paddles and the holes disposed in the sides of the agitators are however not really suitable for wetting the washing inside the drum effectively. The quantity of water scooped will flow away by way of the holes in the agitator sides immediately after the agitator exits from the sump during scooping at the back pressure then resulting at agitator level and then flow back along the inner wall of the drum to the sump, without having wet the washing to any significant degree. It has already been proposed here that the device should be configured in a different manner in the agitator ribs, for example in such a way that during the wetting phases the scooping devices convey the free washing liquor—in other words the quantity of lye in the lower drum space not absorbed by the washing—into an elevated position and pours it from there onto the washing or sprays it from above onto the items to be washed.

A further washing machine drum with agitator ribs configured as a scooping device is known from EP 0 245 721 A1, wherein the agitator hollows are bounded by an agitator base disposed in the drum contour and having paddles and are divided into chambers perpendicular to the drum axis. At least one paddle is assigned to each chamber, so that the paddles of respectively adjacent chambers are assigned to different drum rotation directions and are oriented in an opposing manner to the paddle of the adjacent chamber, with the scooping devices being configured and disposed in such a manner that during the wetting phase they discharge the quantities of water into the interior of the drum at the earliest from a height in the region of the second eighth of the drum rotation, calculated from the lowest point, to at the latest the end of the seventh eighth of the drum rotation. However with this arrangement the volume of lye carried along by the agitator ribs is comparatively small.

The object of the present invention is to provide a structurally simple and low-wear option for wetting washing effectively by means of agitator ribs configured as scooping devices.

This object is achieved by a washing machine configured as claimed in claim 1, in the manner that a fixed barrier is present in the hollow space, ascending from the agitator base in direction W of the inflowing lye, forming an open chamber behind it within the hollow space, and that in the lowest position of the agitator the upper edge of the barrier is higher than the level of the lye and the chamber behind the upper edge can be filled by lye washing over the barrier on further rotation of the washing drum.

Advantageous refinements will emerge from the subclaims, also in any combination with each other.

The washing machine is equipped with a washing drum driven in a horizontally rotatable manner about an axis A in the outer tub. Hollow agitators, which carry the washing with them as the drum rotates, project into the washing drum. The number of said agitators is not restricted and is typically around three. Incorporated in each agitator is at least one inlet opening, through which constituent amounts of a free washing liquor located in the lower apex (6 o'clock position) of the outer tub flow into the associated agitator hollow; the number of inlet openings is not restricted. After a further rotation of the agitators into an elevated position the lye present in the agitator hollow pours into the interior of the washing drum, typically by way of pouring openings in the top region of the agitator.

The inlet opening is incorporated in an agitator base disposed in the shell of the washing drum. A fixed barrier ascending from the agitator base is also present in the agitator hollow, forming an open chamber. Lye flowing over the barrier is retained in the chamber. The chamber is configured and disposed in such a manner that as the washing drum rotates through the free washing liquor or lye the barrier can be filled with lye entering from the associated inlet opening, even if the fill level of the lye reserve is lower than the upper edge of the barrier. This is achieved in that the kinetic energy of the lye flowing into the hollow space of the agitator or its back pressure is sufficient to overcome the barrier. As the washing drum rotates through the free washing liquor, the lye is washed in through the inlet opening with a kinetic energy relative to the washing drum. The lye then strikes the barrier, washes over it and thus enters the chamber behind the barrier. The barrier ascends from the agitator base. However it does not have to be part of the drum contour but can be configured as an insert for example.

As it does not have to be structured and requires no moving parts, the barrier can be produced and incorporated easily and economically and can be operated with a low level of wear. Because the chamber can be filled beyond the fill level of the lye reserve and generally demonstrates a good retaining effect, a comparatively large quantity of lye can be carried along and poured out over the washing. The washing effect per unit of time (washing efficiency) enhanced in this manner means that a shorter program time can be achieved, which in turn reduces heating time and therefore energy consumption. On the other hand the total quantity of washing liquor can alternatively be reduced, which, because it requires less heating power, also reduces energy consumption as well as water consumption.

The height, form and location of the barrier are favorably selected so that a maximum fill results, for example as a function of the rotation speed of the drum and the fill level of the lye. These parameters are typically determined for the different wash phases (wetting phase, rinse phase, etc.) by a control program, so that the barrier can be tailored structurally to a specific washing machine.

The barrier is advantageously inclined away from the associated inlet opening, so that the lye can flow easily over the barrier, which is also favorably present as a wall running parallel to the drum shell.

The barrier can have an additional rib, which is fixed to the drum contour, for example by riveting or welding. The chamber can however also be a trough-type insert in the agitator, the trough base of which is at least partially in contact with the agitator base. The barrier then corresponds to one wall of the trough, with the other wall being in contact for example with an agitator side or lying parallel to this at a distance or even being (jointly) formed by the agitator side. In a further embodiment the barrier or wall can be configured as an inwardly folded peripheral region of the inlet opening, for example as an inwardly peripheral channel of the—preferably slot-type—inlet opening.

To increase the inflowing quantity of lye and lye speed it is advantageous if the inlet opening is provided with a scooping device disposed on the outer drum periphery, for example a scoop opening toward the direction of rotation.

If an improved washing spray is required in both rotation directions, the agitators can be divided into a number of sections in a direction parallel to the drum shell, said sections being oriented alternately toward opposing rotation directions and only demonstrating the desired effect in these. The sections can for example be constructed as mirror images in the rotation direction.

The washing machine is illustrated in more detail schematically in the exemplary embodiments below. Components with the same functional effect are given the same reference characters here for better clarity.

FIG. 1 shows a sketch of a segment of a washing machine with a horizontally rotatable washing drum,

FIG. 2 shows a further sketch of a conventional washing drum in a first rotation position,

FIG. 3 shows a further sketch of the washing drum according to FIG. 2 in a second rotation position,

FIG. 4 shows a sketch of a washing drum of the inventive washing machine in a rotation position similar to that of FIG. 2,

FIG. 5 shows a sketch of the washing drum according to FIG. 4 in a rotation position similar to that of FIG. 3,

FIG. 6 shows an enlarged detailed view of an inventive washing drum with an agitator in a first embodiment,

FIG. 7 shows an enlarged detailed view of an inventive washing drum with an agitator in a second embodiment,

FIG. 8 shows an enlarged detailed view of an inventive washing drum with an agitator in a third embodiment.

The outer tub 1 of a washing machine in FIG. 1 has an intake opening 2 for lye in its upper region. The lye can consist of water or a mixture of detergent introduced from a detergent dispenser 3 together with supplied water. The base of the outer tub 1, which is at the smallest distance possible from the washing drum 4, has a recess 5, in which the heating element 6 required to heat the lye (shown with a broken line) is disposed. An outlet opening 7 is disposed at the lowest point of the recess 5, said outlet opening 7 being kept sealed by a sealing element 8, while a lye pump (not shown) on the drain pipe 9 is not in suction mode. This sealing element 8 has the task of keeping the space below the drain opening 7 sealed, while the detergent required to wash the washing 10 is within the outer tub 1.

Because a little water and detergent as possible should be used for washing, the quantity of lye required for washing has reduced to such a degree that the washing drum 4 is only slightly immersed in the lye at the bottom of the outer tub 1. However this produces the problem that the washing 10 at the bottom of the washing drum 4 no longer comes into sufficient contact with the lye, so the washing 10 is only wet very slowly and very incompletely. This puts the wash result at risk. The wetting of the washing 10 with lye is improved by the deployment of agitators 11, which are attached to the drum shell 41 and which can fill the respective agitator hollow 13 by way of inlet openings 14 fitted with scooping devices 12 from the lye reserve in the recess 5, as the washing drum 4 rotates, for example in the rotation direction shown by the arrow D. During the upward movement of the agitator 11 this scooped quantity of lye is first buffered and then only discharged by way of outlet openings in the top region of the agitator 11, when the agitator 11 reaches a certain height above the washing 10 in the drum 4. The arrow R shows how the lye, elevated in this manner, sprays over the washing 10.

In the washing drum 4 shown in a simplified manner in FIG. 2 the lowest of the three structurally identical agitators attached to the inside is in its lowest position (lower apex, 6 o'clock position). It is immersed here in the free washing liquor at the bottom of the outer tub and takes lye (shown with a dotted line) into its hollow space 13 by way of the inlet opening 14 equipped with the gill-type scooping device 12 and incorporated in the drum shell. Outlet openings 15 are incorporated in the top region of the agitator 11, being above the lye level Nv here. The lye level Nv is typically filled to a predetermined value, as specified in a wash program, in the case of level-based filling. The rotation of the washing drum 4 in the direction of the arrow D causes the scooping device 12 to fill the hollow space 13 of the agitator 11 higher than would be the case in the static state.

A further agitator 11 shown top left has already reached such a high position that lye contained in it sprays out of the outlet openings 15 into the interior of the drum, as shown by the arrows R. The agitator 11 shown top right has already emptied and can once again scoop lye out of the reserve at the bottom of the outer tub 1 once it has completed the remainder of the rotation.

As the lower agitator 11 (FIG. 3) rotates further, the rotation of the washing drum 4 in the rotation direction D causes it to reach a position, in which the lowest edge of the inlet opening 14 corresponds to the lye level Nv. In this elevated position of the lower agitator 11 shown here, the back pressure has dropped to zero, so the quantity of lye in the lower agitator 11 corresponds to that in the static state, in other words the quantity of lye is defined by the small space behind and below the edge of the inlet opening 14. The further agitators 11 continue to spray lye down or approach the lye reserve empty.

FIG. 4 shows agitators 11′ of an inventive washing machine, in which a slot-type inlet opening 14′ is incorporated in an agitator base 42 disposed in the drum contour. The inlet opening 14′ is equipped in each instance with a paddle 12′.

In contrast to the washing drums 4 shown in FIGS. 2 and 3 a fixed barrier 17 ascending from the agitator base 42 or the drum shell 41 is now present in the respective hollow space 13′ behind the inlet opening 14′ in the rotation direction D. The barrier 17 forms an open chamber 18 in the hollow space 13′. The open chamber 18 is thus bounded by the barrier 17, the agitator base 42 and a side of the respective agitator 11′.

The barrier 17 of the agitators 11′ is configured in a wall shape and ascends from the respective inlet opening 14′ starting at an angle into the hollow space 13′. In the exemplary embodiment shown here the upper edge 171 of the barrier 17 with the agitator 11′ in the 6 o'clock position is higher than the lye level Nv set. During operation of the washing machine lye is washed through the inlet opening 14′ into the hollow space 13′, as shown by the arrow W (dotted line). The kinetic energy of the lye, relative to the washing drum 4, enables the lye to overcome the height difference between the lye level Nv and the edge of the barrier 17. In other words the lye washes over the barrier 17 due to its relative speed and is retained in the chamber 18.

FIG. 5 shows the washing drum from FIG. 4 after a further rotation in the rotation direction D. In contrast to the agitator 11 in FIG. 3 the barrier 17 now retains the lye in its chamber 18 even after a reduction in the back pressure, when the lower agitator 11′ was elevated to the lye level Nv. This allows a more than 80% greater volume of lye to be carried along in the agitator 11′ compared with the agitator 11 in FIG. 3.

During the operation of the washing machine, e.g. in a wetting, wash or rinse phase, the outer tub is first filled with lye, typically in a level-based manner to a fill level Nv. The washing drum 4 is then rotated. As the agitator passes through the lye reserve or the free washing liquor, lye flows through the inlet opening(s) 14′ into the hollow space 13′. If the fill level Nv is lower than the base 42 of the agitator 11′ in the 6 o'clock position, corresponding to its lower apex, with the inventive configuration of the washing drum 4 the lye can still wash over the barrier 17 and be trapped or stored in the chamber 18.

During further rotation of the washing drum 4 the agitator 11′ is moved into an elevated position, in which the lye flows out of the chamber 18 to the outlet openings 15′ and pours through these into the washing drum 4.

The outlet openings 15′ are preferably located in the upper region of each agitator 11′, the top region. This ensures that a large volume of lye is carried along and only sprays out of the agitator, when it is far above the washing.

The inlet opening 14′ can be an individual opening, e.g. in the form of a slot with or without gills or a number of inlet openings can be present for each agitator base 42, e.g. a number of slots or holes.

The agitator 11′ can be divided into sections disposed parallel to the agitator base 42, which is also parallel to the longitudinal axis of the agitator 11′. This is particularly advantageous, if the washing drum 4 is to carry out the moistening process in both rotation directions. The sections can then for example be active alternately in opposing rotation directions, e.g. by reversing the arrangement of the structural features in respect of the rotation direction in an alternating manner.

Of course the barrier is also advantageous in respect of retaining lye in the agitator, when the lye level Nv is above the edge 171 of the barrier as it passes through the lye reserve. The volume of lye carried along is no longer as great as with an undivided hollow space 13′ but it is the same degree greater than with a divided hollow space without a barrier.

As shown in FIG. 6, the barrier 17 can also be configured as an additional rib 19, which in this instance is riveted for example but can also be fixed in another manner. As shown in FIG. 7, it is however also possible for the barrier 17 to be formed by means of a trough-type insert 18 in the agitator 11′, the trough base 201 of which is at least partially in contact with the agitator base 42. The trough can for example be made of metal or plastic. The barrier 17 can also be configured as an inwardly folded peripheral region 21 of the inlet opening, particularly when it is formed from a flat material, as shown in FIG. 8. 

1-8. (canceled)
 9. A washing machine comprising: a washing drum that is driven in a horizontally rotatable manner and located in an outer tub, the drum comprising a drum shell; hollow agitators disposed on the inside of the drum shell, each agitator having an agitator base comprising part of the drum shell, the agitator base having at least one inlet opening for allowing constituent amounts of a lye disposed in a lower apex of the outer tub to flow into the hollow space of the agitator; outlet openings in a top region of each agitator which is removed from the base thereof, for allowing lye to pour out of the hollow space of each agitator after rotation of the washing drum moves each agitator into an elevated position; and a fixed barrier located in the hollow space of each agitator, ascending from the agitator base in the direction of lye flowing into the hollow space, forming an open chamber on one side of the hollow space, and arranged such that when the agitator is in the lowest position due to rotation of the washing drum an upper edge of the barrier is higher than a level of lye in the hollow space for having the open chamber fill with lye due to lye washing over the barrier upon further rotation of the washing drum.
 10. The washing machine as claimed in claim 9, wherein the barrier further comprises a wall running parallel to the drum shell, the wall being inclined away from the associated inlet opening, and the inlet opening disposed in front of the barrier in the rotation direction.
 11. The washing machine as claimed in claim 10, wherein the barrier comprises an additional rib.
 12. The washing machine as claimed in claim 10, wherein the barrier and the chamber are formed as a trough-type insert in the agitator, a trough base of the insert being at least partially in contact with the agitator base.
 13. The washing machine as claimed in claim 10, wherein the barrier comprises an inwardly folded peripheral region of the inlet opening.
 14. The washing machine as claimed in claim 9, wherein the inlet opening further comprises a scoop disposed on the drum shell, the scoop opening in the rotation direction.
 15. The washing machine as claimed in claim 9, wherein the agitator is divided into a number of sections in a direction parallel to the drum shell, the inlet openings of the sections being oriented alternately toward opposing rotation directions.
 16. A method for operating a washing machine, the method comprising: providing a washing machine having a washing drum comprising a drum shell, the washing drum drivable in a horizontally rotating manner and located in an outer tub, hollow agitators disposed on the inside of the drum shell, each agitator having a base comprising part of the drum shell and having an inlet opening, outlet openings in a top region of each agitator, and a fixed barrier located in the hollow space of each agitator ascending from the agitator base to form an open chamber on one side of the hollow space; filling the outer tub with lye up to a fill level, the fill level being below an upper edge of the fixed barrier of the agitator when the agitator is located in the lower apex as a result of rotation of the washing drum; rotating the washing drum; allowing lye to flow into the inlet opening as a result of the rotation, the inlet opening located such that as the agitator passes through the lye, lye flows through the inlet opening into the respective agitator, washes over the barrier and enters the chamber, where it is stored; and further rotating the washing drum for moving the agitator into an elevated position, the outlet openings located at a position for having the lye flow out of the chamber through the outlet openings in the agitator to pour into the interior of the washing drum. 